/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package com.sun.org.apache.xml.internal.security.algorithms;

import java.security.MessageDigest;
import java.security.NoSuchProviderException;

import com.sun.org.apache.xml.internal.security.signature.XMLSignatureException;
import com.sun.org.apache.xml.internal.security.utils.Constants;
import com.sun.org.apache.xml.internal.security.utils.EncryptionConstants;
import org.w3c.dom.Document;

/**
 * Digest Message wrapper & selector class.
 *
 * <pre>
 * MessageDigestAlgorithm.getInstance()
 * </pre>
 */
public class MessageDigestAlgorithm extends Algorithm {

  /**
   * Message Digest - NOT RECOMMENDED MD5
   */
  public static final String ALGO_ID_DIGEST_NOT_RECOMMENDED_MD5 =
      Constants.MoreAlgorithmsSpecNS + "md5";
  /**
   * Digest - Required SHA1
   */
  public static final String ALGO_ID_DIGEST_SHA1 = Constants.SignatureSpecNS + "sha1";
  /**
   * Message Digest - RECOMMENDED SHA256
   */
  public static final String ALGO_ID_DIGEST_SHA256 =
      EncryptionConstants.EncryptionSpecNS + "sha256";
  /**
   * Message Digest - OPTIONAL SHA384
   */
  public static final String ALGO_ID_DIGEST_SHA384 =
      Constants.MoreAlgorithmsSpecNS + "sha384";
  /**
   * Message Digest - OPTIONAL SHA512
   */
  public static final String ALGO_ID_DIGEST_SHA512 =
      EncryptionConstants.EncryptionSpecNS + "sha512";
  /**
   * Message Digest - OPTIONAL RIPEMD-160
   */
  public static final String ALGO_ID_DIGEST_RIPEMD160 =
      EncryptionConstants.EncryptionSpecNS + "ripemd160";

  /**
   * Field algorithm stores the actual {@link java.security.MessageDigest}
   */
  private final MessageDigest algorithm;

  /**
   * Constructor for the brave who pass their own message digest algorithms and the
   * corresponding URI.
   */
  private MessageDigestAlgorithm(Document doc, String algorithmURI)
      throws XMLSignatureException {
    super(doc, algorithmURI);

    algorithm = getDigestInstance(algorithmURI);
  }

  /**
   * Factory method for constructing a message digest algorithm by name.
   *
   * @return The MessageDigestAlgorithm element to attach in document and to digest
   */
  public static MessageDigestAlgorithm getInstance(
      Document doc, String algorithmURI
  ) throws XMLSignatureException {
    return new MessageDigestAlgorithm(doc, algorithmURI);
  }

  private static MessageDigest getDigestInstance(String algorithmURI) throws XMLSignatureException {
    String algorithmID = JCEMapper.translateURItoJCEID(algorithmURI);

    if (algorithmID == null) {
      Object[] exArgs = {algorithmURI};
      throw new XMLSignatureException("algorithms.NoSuchMap", exArgs);
    }

    MessageDigest md;
    String provider = JCEMapper.getProviderId();
    try {
      if (provider == null) {
        md = MessageDigest.getInstance(algorithmID);
      } else {
        md = MessageDigest.getInstance(algorithmID, provider);
      }
    } catch (java.security.NoSuchAlgorithmException ex) {
      Object[] exArgs = {algorithmID, ex.getLocalizedMessage()};

      throw new XMLSignatureException("algorithms.NoSuchAlgorithm", exArgs);
    } catch (NoSuchProviderException ex) {
      Object[] exArgs = {algorithmID, ex.getLocalizedMessage()};

      throw new XMLSignatureException("algorithms.NoSuchAlgorithm", exArgs);
    }

    return md;
  }

  /**
   * Returns the actual {@link java.security.MessageDigest} algorithm object
   *
   * @return the actual {@link java.security.MessageDigest} algorithm object
   */
  public java.security.MessageDigest getAlgorithm() {
    return algorithm;
  }

  /**
   * Proxy method for {@link java.security.MessageDigest#isEqual}
   * which is executed on the internal {@link java.security.MessageDigest} object.
   *
   * @return the result of the {@link java.security.MessageDigest#isEqual} method
   */
  public static boolean isEqual(byte[] digesta, byte[] digestb) {
    return java.security.MessageDigest.isEqual(digesta, digestb);
  }

  /**
   * Proxy method for {@link java.security.MessageDigest#digest()}
   * which is executed on the internal {@link java.security.MessageDigest} object.
   *
   * @return the result of the {@link java.security.MessageDigest#digest()} method
   */
  public byte[] digest() {
    return algorithm.digest();
  }

  /**
   * Proxy method for {@link java.security.MessageDigest#digest(byte[])}
   * which is executed on the internal {@link java.security.MessageDigest} object.
   *
   * @return the result of the {@link java.security.MessageDigest#digest(byte[])} method
   */
  public byte[] digest(byte input[]) {
    return algorithm.digest(input);
  }

  /**
   * Proxy method for {@link java.security.MessageDigest#digest(byte[], int, int)}
   * which is executed on the internal {@link java.security.MessageDigest} object.
   *
   * @return the result of the {@link java.security.MessageDigest#digest(byte[], int, int)} method
   */
  public int digest(byte buf[], int offset, int len) throws java.security.DigestException {
    return algorithm.digest(buf, offset, len);
  }

  /**
   * Proxy method for {@link java.security.MessageDigest#getAlgorithm}
   * which is executed on the internal {@link java.security.MessageDigest} object.
   *
   * @return the result of the {@link java.security.MessageDigest#getAlgorithm} method
   */
  public String getJCEAlgorithmString() {
    return algorithm.getAlgorithm();
  }

  /**
   * Proxy method for {@link java.security.MessageDigest#getProvider}
   * which is executed on the internal {@link java.security.MessageDigest} object.
   *
   * @return the result of the {@link java.security.MessageDigest#getProvider} method
   */
  public java.security.Provider getJCEProvider() {
    return algorithm.getProvider();
  }

  /**
   * Proxy method for {@link java.security.MessageDigest#getDigestLength}
   * which is executed on the internal {@link java.security.MessageDigest} object.
   *
   * @return the result of the {@link java.security.MessageDigest#getDigestLength} method
   */
  public int getDigestLength() {
    return algorithm.getDigestLength();
  }

  /**
   * Proxy method for {@link java.security.MessageDigest#reset}
   * which is executed on the internal {@link java.security.MessageDigest} object.
   */
  public void reset() {
    algorithm.reset();
  }

  /**
   * Proxy method for {@link java.security.MessageDigest#update(byte[])}
   * which is executed on the internal {@link java.security.MessageDigest} object.
   */
  public void update(byte[] input) {
    algorithm.update(input);
  }

  /**
   * Proxy method for {@link java.security.MessageDigest#update(byte)}
   * which is executed on the internal {@link java.security.MessageDigest} object.
   */
  public void update(byte input) {
    algorithm.update(input);
  }

  /**
   * Proxy method for {@link java.security.MessageDigest#update(byte[], int, int)}
   * which is executed on the internal {@link java.security.MessageDigest} object.
   */
  public void update(byte buf[], int offset, int len) {
    algorithm.update(buf, offset, len);
  }

  /**
   * @inheritDoc
   */
  public String getBaseNamespace() {
    return Constants.SignatureSpecNS;
  }

  /**
   * @inheritDoc
   */
  public String getBaseLocalName() {
    return Constants._TAG_DIGESTMETHOD;
  }
}
